This is a $20 single speed spacer and cog kit solution to your problem. This isn't a fixed rear wheel right? With the spacers you can move the single speed cog anywhere on your freehub to line up with your crankset up front.
Redishing your wheel will almost definitley not be necessary.
I removed the cassette and the wheel is dished.
This is ambiguous. Wheels with gears on it are always dished.